#include<stdio.h>
#include<math.h>
	int main()
	{  
	  /*********Begin*********/
      float score;
	  int x;
      scanf("%f",&score);
      if(score>=0&&score<=100)
      {
          x=score/10;
          switch(x)
          {
              case 10:printf("A");break;
              case 9:printf("A");break;
              case 8:printf("B");break;
              case 7:printf("C");break;
              case 6:printf("D");break;
              default:printf("E");
          }
      }else 
       printf("Score is error!");   
      
      
	  /*********End**********/ 
       return 0;
	}
